I've written a program that has multiple test fixtures. When a test is initiated the fixture channel settings are used to create the correct tasks and open relays for the selected fixture. A sample is then heated to different setpoints with a PID heating loop, and data is collected and analyzed.
When I create the thermocouple task, i'm using a sample clock node set to continuous readings, 1 channel, 50 readings per second. The PID node does not have any timing specified. I did this to limit the speed of the PID loop, and so that I could convert loop count to seconds to display on the graph. Is this correct and OK to control the timing? Previously I had ran into problems if the thermocouple timing was faster than the PID loop and older data was being displayed instead of most recent measurements. My current code seems to prevent any issues, but I'm not sure if its the correct setup. I've attached two images of the thermocouple create channel code and the PID subvi code (the subvi is inside a loop but not shown).
Lastly I have a simpler subvi for testing the thermocouple readout running a full test. Typically when I run this code, the very first temperature that is displayed is off, such as showing 200 on a room temperature thermocouple. It quickly corrects to the correct measurement, but because there is a 500ms wait between each reading, it is noticeable. Is there something that I'm doing wrong causing this? Is it because I create a thermocouple channel and start the task before i've closed the relays that connect the thermocouple? Or am I just taking a reading too soon after the relay is closed? Does the code itself look ok?
Thanks
